What is a condition action rule?

What is a condition action rule?

An event-condition-action rule (ECA rule) is the method underlying event-driven computing, in which actions are triggered by events, given the existence of specific conditions. Events with significance to the system are identified within an event-driven program.

What is the event condition action rule used in active database?

PDL “uses the event–condition–action (ECA) rule paradigm of active databases to define a policy as a function that maps a series of events into a set of actions.” This approach is interesting because in addition to policy rules, there are policy-defined event propositions that allow groups of simple events to trigger …

What is an ECA rule?

The ECA rule concept states that when an event occurs, the condition is evaluated and if the condition is satisfied, the action is executed.

Which of the following database systems can provide rules that can automatically initiate actions when certain events and conditions occur?

Active database system is a database system which is capable of generating a certain action automatically if it detects an event that meets certain conditions.

What is ECA model in database?

Event condition action (ECA) is a short-cut for referring to the structure of active rules in event driven architecture and active database systems. Such a rule traditionally consisted of three parts: The event part specifies the signal that triggers the invocation of the rule.

Can triggers be enabled or disabled?

To enable a trigger, causes it to fire when any Transact-SQL statements on which it was originally programmed are run. Triggers are disabled by using DISABLE TRIGGER. DML triggers defined on tables can also be disabled or enabled by using ALTER TABLE.

What is trigger explain with example?

Trigger: A trigger is a stored procedure in database which automatically invokes whenever a special event in the database occurs. For example, a trigger can be invoked when a row is inserted into a specified table or when certain table columns are being updated.

What is SQL ECA?

What is Rule Manager?

Rules Manager, a feature of Oracle Database, offers interfaces to define, manage, and enforce complex rules in the database. The five elements of a Rules Manager application are: An event structure you define as an object type with attributes that describe specific features of an event.

What happen when a trigger is disabled?

Disabling a trigger does not drop it. The trigger still exists as an object in the current database. However, the trigger does not fire when any Transact-SQL statements on which it was programmed are executed. Triggers can be re-enabled by using ENABLE TRIGGER.

Are views stored in memory?

The view is a query stored in the data dictionary, on which the user can query just like they do on tables. It does not use the physical memory, only the query is stored in the data dictionary. It is computed dynamically, whenever the user performs any query on it.

What are the types of triggering?

What are the types of triggers?

• DDL Trigger.
• DML Trigger.
• Logon Trigger.